I have heard $10 each way. I have also heard the beach doesn't have much. So my restrooms or restuarants. So I'm not sure now long you would want to say there. My plan is to hang out a Medano beach close to the restrooms. They also have water sports at an extra charge: jet skis, parasailing, banana boat ride etc.

I was there last February and they were $10 per person round trip. They're really nice guys who will take you over to see the seals play around on the rocks on the way over to Lovers Beach. They will drop you off and ask what time you want to come back. The whole trip is about 10 minutes each way. They blast the music and make the ride really fun!

Be aware that the surf pounds onto Lover's Beach with tremendous force.
Swimming there is not recommended as there are no lifeguards. Have the boat operator pilot the boat around the arch as there are great photo opportunities.
I was able to photo some sea lions sunbathing on the rocks. Be sure to wear lots of sun screen and carry some water. We stayed approx. one hour.